The Burgess Concentric Zone Model

Burgess studied Chicago in the 1920s and noticed cities don't grow randomly. They grow outward from the center the way ripples spread from a dropped stone. At the middle sits the central business district, packed with offices, shops, and the highest land values, so nobody builds housing there if they can avoid it. Right next to that sits the zone of transition, old housing mixed with small factories and warehouses, cheap because it's noisy, polluted, and uncertain. New immigrants and the poorest residents settle there because rent is low and jobs are walkable, even though the area is physically rough.

Each ring beyond that holds a step up in income: a zone of working-class housing for people one generation removed from the zone of transition, then better residential housing, then a commuter zone at the very edge where wealthier people buy space and accept a long commute downtown in exchange. The model says these rings aren't fixed forever. As a city keeps adding population, every group gets pushed slightly farther out by the next wave of arrivals behind it, so the whole pattern expands outward like tree rings, with boundaries drifting rather than staying put.

This model sits first in the unit's lineup of urban models because it's the simplest starting point: a city shaped only by distance from one center. The models that follow it, Hoyt's sectors and the multiple nuclei model, correct its biggest weakness, that real cities have highways, rivers, and multiple job centers that bend the rings into wedges and clusters instead of clean circles.